The connecting rod of an internal combustion engine or a reciprocating compressor is usually affixed to the crankshaft of the engine or compressor by placing a bearing cap opposite the connecting rod about the bearing on the crankshaft and bolting the bearing cap to the connecting rod. In order to accomplish this, the mechanic ordinarily must place a wrench on the bolt head while the nut is tightened on the opposite end of the bolt. In some engines access to the top and bottom of the connecting rod in the vicinity of the crankshaft may be accomplished by rotation of the crankshaft, thereby permitting relatively easy assembly. However, the space available in some engines or compressors makes it impossible to reach the head end of the bolt in order to fix a wrench to the connecting rod bolt head.
It has therefore become the practice to machine a ledge having a flat surface and a vertical back wall on the rod portion of the connecting rod/cap combination so that some sort of the locking may be accomplished between the bolt head and connecting rod. The machining process quite frequently will cause a sharp edge or an area of stress concentration in the metal of the connecting rod. After many cycles of the crankshaft, the loads induced into the connecting rod can cause the connecting rod to fail through these areas of stress concentration. Furthermore, the removal of metal in a connecting rod may tend to weaken the connecting rod unnecessarily. In the past, this has been overcome by making a larger forging than necessary in order to achieve the necessary ledge for retaining the bolt head while retaining the required strength.
A single retaining mechanism for a single bolt on a flat surface would be possible, but would rotate unless held stationary. This may be overcome by folding portions of the retainer, one portion folded up against the head of the bolt with the other portion folded down over the material being fastened. Such retainers may, however, be difficult to use.
The present invention is directed to overcoming one or more of the problems as set forth above.